This invention relates to a magnetic pick up system and associated method. More specifically, this invention relates to a magnetic pick up system and method for picking up articles from a railway roadbed.
When laying a new railroad track or when laying new rails upon a previously existing railroad track, it is necessary to provide tie plates upon the railroad ties. One tie plate is required for each side of each tie and typically more than 3,000 tie plates would be required for one mile of track. The tie plates may be manually placed upon each of the ties. Alternately, various machines have been developed in an attempt to avoid the high labor associated with manual placement of the tie plates. As such machines are required to place a large number of tie plates upon ties, it will be appreciated that they require the feeding of a large number of tie plates to them. A crane with an electromagnetic pick up head or other techniques have been used to pick up tie plates along the roadbed. The tie plates will have been previously distributed along the roadbed by another vehicle.
Although prior techniques such as cranes with electromagnetic heads have generally been adequate to lift the tie plates off the roadbed and into a storage bin or similar part of the tie plate placing vehicle, they have often been subject to one or more of several disadvantages.
Prior techniques of loading tie plates onto the tie plate placing vehicles have often required that the vehicle stop its movement. For example, the crane arrangement with an electromagnetic head may fail to pick up some tie plates if the vehicle is moving.
The present inventor's prior U.S. Pat. No. 4,225,429 issued on Sept. 30, 1980 discloses a "Vehicle For Cleaning Railway Roadbeds Of Magnetic Articles" using a lower roller or pulley provided with permanent magnets in order to pick up magnetic articles from a railway road bed. The articles are carried up to a vehicle by a conveyor belt.
The present inventor's prior U.S. Pat. No. 4,478,152 entitled "Railroad Scrap Pick Up Machine" issued on Oct. 23, 1984 discloses an arrangement using a magnetic wheel with permanent magnets which are used to pick up tie plates from a railroad bed.
The above and other techniques for picking up magnetic objects from a roadbed have several disadvantages. Those systems which use a magnetic wheel travelling along the roadbed have a tendency to wear out. Additionally, obstacles in the roadbed, or simply a rise in the level of the roadbed, may cause damage to the magnetic wheel. On the other hand, spacing of such a magnetic head above the ground will likely cause it to fail to pick up a tie plate or other object which is supposed to be lifted from the ground.
A further disadvantage of numerous prior techniques for picking up magnetic articles from a railway roadbed is that such techniques often either require a large number of magnetic pick up heads (thus increasing costs and complexity) in order to pick up magnetic articles across the width of the roadbed or they lack the ability to conveniently pick up magnetic articles which are spaced in a sideways direction (i.e., spaced perpendiculary to the direction in which the rails or rail extend).
A further disadvantage of numerous prior techniques is their inability to provide an arrangement where an operator may control a magnetic pick up head from a position adjacent to the magnetic pick up head (as opposed to a position up on a vehicle).
Yet another disadvantage of numerous prior techniques is the inability of magnetic pick up heads to be capable of convenient up and down movement as the roadbed terrain and obstacles dictate.